Hyponatremia is a common electrolyte disturbance occurring in critically ill patients. Mild hyponatremia (serum sodium, <135 mmol per liter) occurs in 15 to 22% of these patients and in approximately 7% of ambulatory patients; moderate hyponatremia (serum sodium, <130 mmol per liter) occurs in 1 to 7% of hospitalized patients. Symptoms range from nausea and malaise, with mild reduction in sodium, to lethargy, decreased level of consciousness, headache and if severe seizures and coma. Overt neurological symptoms most often are due to very low serum sodium levels usually <115 mEq/L, resulting in intracerebral osmotic fluid shifts, and brain edema, In patients with acute ST-elevation myocardial infarction, the presence of hyponatremia on admission or early development of hyponatremia is an independent predictor of 30-day mortality, and the prognosis worsens with the severity of hyponatremia.In our study Euvolemic was the most common type of Hyponatremia (55%) followed by Hypervolemic (25%) and Hypovolemic (20%). The most common cause of Hyponatremia was SIADH (34%) followed by Drugs (15%), Renal failure (12%), Heart failure (11%), Gastrointestinal loses (9%), Renal and Heart failure (9%), Endocrine disorders (4%), Chronic liver disease (4%), Burns(1%) and Cerebral salt wasting (1%). The mean ICU stay mild, moderate and severe Hyponatremia was 5.5±0.49 days, 5.1±0.38 days and 5.3±0.52 days respectively in our study.

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Dr Raghav R Nagpal

Resident, Department of General Medicine,

MGM Hospital, Navi Mumbai